Nanotechnology, manipulating atoms and molecules at the nanometer level, is an emerging technology, introducing new dimensions to science and technology by the convergence of traditional disciplines. In the early stage of nanotechnology development and diffusion, many expected benefits have not yet been fully accomplished. However, researchers of many countries in the scientific disciplines aggressively got involved in the relevant research as a parallel way to boost nanotech competitiveness through academic research, and corporations direct their R&D activities towards the exploration of nanotech opportunities. Through a combination of quantitative (bibliometric exploration) and qualitative method (primary data analysis), the paper attempts to establish the trend of science disciplines' knowledge fusion into nanotechnology field. In terms of fusing disciplines together, a number of approaches were considered: i) looking for nanoscientific output of journals of general disciplines categorized by ISI (find to what extent were nanotech papers coming from scientific disciplines over time and how it has changed over time?); ii) to look for a set of nanoscience papers in each disciplinary journals at present, 5 and 10 years ago and their reference citations (classify the citing references into disciplines using ISI journal based classification scheme and what proportions were coming out or linking with each disciplines. This study also identified the concerned factors driving multi-disciplines' fusion into nanotech, that would be a good evidence of fusing previously separate disciplinary activities into nanotech. The research offers useful insights for science & technology policy makers as well as for researchers of traditional science fields in the global community, revealing fusion trend of the emerging nanotechnological systems, existing domain-level competencies and differences between disciplines.